S-tec 55x Installation Manual -

Requires a standard 1X or 4X bootstrap heading output to enable heading select mode.

Turn on the avionics master. The S-TEC 55X should run through a brief internal diagnostic self-test, illuminating all display segments.

Allows GPS Steering (GPSS), VOR tracking, and localizer/glideslope capture. S-tec 55x Installation Manual

Verify that pressing the AP DISC switch on the control yoke instantly drops the autopilot engagement. Diagnostic Matrix Potential Cause Corrective Action Autopilot disengages immediately Open circuit in trim or servo harness Check continuity of the disconnect loop Sluggish response to turns Bridle cable tension too low Re-tension cable to STC specifications Heading tracks with an offset HSI/DG alignment error Calibrate the heading datum voltage 6. Flight Testing and Sign-Off

Probable Cause : Bridle cables are too loose, or the turn coordinator is loose in its panel cutout. Requires a standard 1X or 4X bootstrap heading

Manually move the control stick/yoke through its full range of motion (left, right, forward, aft). Ensure there is zero rubbing, binding, or unusual resistance from the autopilot servos.

A modified turn coordinator that outputs an analog roll rate signal to the autopilot computer. Flight Testing and Sign-Off Probable Cause : Bridle

Engage HDG mode, turn the heading bug right, and verify the control yoke turns smoothly to the right without catching or reversing. 6. Flight Testing and Calibration

The S-TEC System 55X is a high-performance, rate-based autopilot found in thousands of general aviation aircraft. Installing, troubleshooting, or upgrading this system requires strict adherence to its official installation documentation. This comprehensive guide breaks down the core technical requirements, wiring configurations, and calibration procedures typically detailed in the S-TEC 55X installation manual. 1. Document Overview and FAA Compliance

Connects to the localized radio magnetic indicator (RMI) or HSI via a standard standard AC bootstrap or DC analog heading error signal.